Tension apparatus.



G. s. WILLIAMSON III c. E. IIIIANIJELICN.l

TENSION APPAIIAIus.

APPLICATION FILED AUG. 5. |91 l.

1,1 60,55. Patented Nv. 16, 1915.

6 SHEETS-SHEET l.

G. s. WILLIAMsoN 1 c. E. MANDELICK.

TENSION APPARATUS.

APPLlcArloN FILED Aus.5. 1911.

1 1 60,556, Panama Nov. 16, 1915.

6 SHEETS-SHEET 2.

G. S. WILLIAMSON & C. E. IVIANDELICK. TENSION APPARATUS. APPLICATION msnAusf. aan.

1,1 60,556, Patented Nov. 16, 1915.

5 SHEETS*SHEET 3.

mprlmTI-lmll-IIIIIIIII I.'

WILLIAMSON ac. E. MYANDELICII.

TENSION APPARATUS.

APPLICATION FILED was. I9II.

Patented Nov. 16, 1915.

6 SHEETS-SHEET`4.

G. S. WILLIAMSON. & C. E. MANDELICK.

TENSION APPARATUS. APPUcATloN msn Aue.5. 19u.

Patented Nov. 16,1915.

6 SHEETS-SHEET 5.

G. S. WILLIAMSON 61 C. E. MANDELICK.

TENSION APPARATUS.

APPucATlo'N ngen Aus.5. 1911.

1,1 60,556- Patented Nov. 16, 1915.

' y t l l 6 SHEETS-SHEET 6.

/Zyf A GLENN l S. WILLIAMSON,

OF NEW YORK, N. Y., AND CHARLES E. MANDELICK, OF RIDGEFIELD PARK, NEWJERSEY.

TENSION APPARATUS.

Application fr led August 5, 1911. Serial No. 642,544.

To (/ZZ inkom it may concern.'

Be it known that we. GLENN S. WILLIAM- sox and CIL-xmms E. MANDELICK,citizens of the United States, and residents, respectively, of New York.borough of Manhattan. county and State of New York, and Ridgefield Park,county of Bergen, State of New Jersey, have invented certain new anduseful Improvements in Tension Apparatus, of which the following is aspecification.

This invention relates to means for controlling the tension of materialin winding or unwinding. involving rolls or reels the diameter of whichvaries as-the material is 'Olllld 01' llIVOlllld. i

The invention as illustrated is shown as applied more particularly forthe control of the tension of the paperdrawn from its roll b v a rotaryweb printing press. In such printing presses it is of great im- Iportance that the roll be at all times prevented from overrunning. Thedanger of this exists particularly when the roll is new, since at thistime its weight and conse quently its inertia is large, and at the sametime the leverage exerted by the traveling web to turn the roll ismaximum. At the outset. with a new roll, the braking effect must beconsiderable. As the roll diminishes in size and the leverage of thetravel- `theweb throughout the unwinding of the roll. The meansheretofore practically employed has been a hand-operated friction brake.This means has proved only partially satisfactory.

The object of this invention is to provide a thoroughly practicalautomatic apparatus Awfor maintaining a uniform tension on the web whilethe latter is traveling into the.

press at normal lineal speed.

A further object is to cause the braking effect to be developed aftertheroll is first .placed in motion. so that the resistance of thebrakeis not added, at the very outset, to the resistance of inertia, and tocause the braking effect to increase automatically to a maximumcoincident with the arrival of Specification -of ,Letters Patent.

Patented Nov. 16, 1915.

the web at normal lineal speed, after which the brakmg effect isdiminished as the roll dlminishes in size.

A further object is to cause the braking effect to be again increasedwhen the press and the roll die down, at which time the 4- roll wouldotherwise Outrun the press.

-A further object is to enable the accomplishment of all these resultsby a single means under the control of the angular velocity of the roll.

A further object is to provide automatic means for preventing thebraking means from returning to normal starting condi-` To accomplish'these ends We employ' means, including a braking electric generatordriven by the roll-'support, whereby the braking effect offered to theturning of the roll is controlled automatically, during running atnormal lineal .speed of the web, at starting, and at stopping.Preferably-the instrumentalities for varying the braking effect of thegenerator arek controlled by the angular velocity of the roll;v so that,maximum braking is attained at or about the same time that the linealspeed of the web arrives at maximum, and thereafter the increasingangular velocity ofthe roll', 'corresponding to the decreasing sizethereof, causes these instrumentalities to decrease the braking effectto minimum With minimum size of the roll. An advantage of this is thatas the velocity of the roll dies down to the lower speeds, due to theslowing down i speed of the armature increases.

2 income Preferably, the support to which the generator is connected isa spindle or axial support. The generator may be directly connected tothe support, or it may be geared thereto.

The most preferable embodiment of means for placing the variation of,the braking effect under the control of the .angular velocity of therolls, includes a floating or rotatable field or other-.magnetic membermoved by the torque ofthe armature. In its rotation under the torque ofthe armature this floating magnetic member operates or controlsinstrumentalities to reduce the braking effect of the generator on thepaper roll. This is best accomplished by providing a rheostat orvariable resistance which is placed so as to be controlled by thefloating magnetic member, though it will be obvious that other forms ofimpedance may be employed. As the floating member rotates under thetorque of the armature it operates to cut in or to cut out more of theresistance, as the nature of the wiring may be, to cause the currentgenerated by the dynamo to ldecrease as the The most direct, but not theonly way of accomplishing this is to place variable resistance in serieswith the armature and to provide mechanical means whereby thefield-frame progressively cuts more resistance into series with thearmature as the speed of the latter increases.

In order to enable the floating member to be progressively rotated underthe diminishing torque of the armature we provide means for resistingthe turning of the member, which means has an automatically de creasingeffect as the member turns. A desirable form of such means is amechanical resistance, and a simple form of mechanical resistance is aweight and connections between the weight and the floating memberwhereby the moment of the weight decreases as the rotation of the memberprogresses. For lessening the moment of the weight we prefer to employ acam whereby the leverage of the weight is reduced. This means forexerting diminishing resistance to the .turning of the floating memberalso operates to restore the field-frame to normal position uponstopping of the roll; so that when the netic member against return tonormal posig latch or other suitable means may coperate with thefield-frame for this purpose. When la small roll is again started afterthe latch has come into operation, the braking effect will not gothrough the completecycle, butwill increase up to the degree determinedby the position of the latch. It is desirable, however, to provide meanswhereby this latch is prevented from holding the fieldframe at thepredetermined degree of rotation, when the press is started up with anew, large roll placed on the bearings. To this end, we prefer to employmeans whereby the insertion of a new roll necessitates the releasing ofthe latch so that the field-frame may be returned to normal position. Wealso provide means, which may be embodied in the same mechanism as thepreceding means, whereby the insertion of a new roll vcauses thepositive return of the field-frame irrespective of the action of theweight.

In order to assist the-braking effect of the generator to stop the rollupon either' a gradual stop or an emergency stop of the press, we employan electric magnetic brake, which is energized b v the act of stoppingthe press. Preferably the coils of this brake are supplied with currentfrom the armature of the braking generator. The brake may 'coperate withthe rotatable support of ,action is secured. This sudden increase invthe braking current not only causes the braking generator to act as adynamic brake but also causes an abnormally strong current to flowthrough the coils of the magnetic brake. which is supplied from thearmature of the generator. and which is caused to be energized throughthe emergency stopping of the press.

It is obvious that the strength ofthe braking `current generated by thedynamo. and therefore the magnitude of the braking effect of thegenerator on the paper roll, is dependent directly upon the value of theresistance elements associated with the armature circuit and theformation ofthe cam whereby the moment of the force opposing therotation of the field-frame is opposed with diminishing effect. IVeprefer to utilize resistance elements having varying values, increasingfrom a small degree of resistance for those first cut in to a highdegree of resistance for those last cut in. The resistance elementsfirst included in the circuit are of too low a value to prevent thecurrent increasing in strength up to that generated by the normal speedof the press, but thereafter the elements cut in are of sufficientvalues to cause the current to be progressively diminished.

A desirable feature of the invention is the production of means wherebythe press is automatically stopped when the roll has attained a.predetermined velocity corresponding to the close approach of theexhaustion of the web wound thereon.

A further object of the invention is to embody the variousinstrumentalities in an assemblage which occupies comparatively littlespace, in the most convenient location, and which may be applied to andremoved from the roll or its support in the simplest manner, Withoutcomplicating the operation of inserting a new roll.

A. further object of the invention is to provide a novel means ormargin-regulating device, whereby the roll may be adjusted sidewise in amuch more delicate manner than heretofore to keep the web running true.

Having thus briefly described the nature of Iour invention we will nowproceed to a specific consideration of those embodiments of the variousinstrumentalities which eX- perience has shown to. be the best suitedfor the purposes in View, it being understood, however, that numerousother embodiments within the scope of the invention are possible.

In the accompanying views we illustrate the preferred form of theinvention; and in these views:

Figure 1 is a plan View, showing part of the press frame and parts,broken away for economy and space, and the brake apparatus swung awayfrom the press frame; Fig. 2 is a transverse section through the brakeapparatus, part of the section being throughv the generator, and part ina different plane at the region of the shaft that is coupled with theroll spindle; Fig. 3 is a front View of the brake apparatus; Fig. 4 is aside View thereof, parts being broken away; Fig. 5 is a rear viewthereof; Figs. 6 and 7 are views on a smaller scale, corresponding tothe last, showing parts in changed positions; Fig. 8 is a sectional viewin the plane of the shaft that is coupled to the roll spindle; Fig. 9and Fig. 9a are diagrammatic views showing wiring; Fig.,10 is a view ofthe opposite side of the apparatus from that shown in Fig. Ll; Fig. 11is a detail section showing the centrifugal means for controlling theelectromagnetic stopping brake; Fig. 12 is a diagram of wiring; Fig.13is a detail section of the electromagnetic stopping brake; and Fig. 11is a semi-di-y agrammatic view, lshowing a forni of variable resistancewith commutator and brushes that may be employed.

The numeral 1, referring more particularly to Figs. 1 and 2, indicatesthe framework of a rotary web printing press; 2 are ed as a unit so thatit may be swung later-v ally toward and from the press, into and out ofcoupled relation with the spindle 3. To this end we provide a suitablesupport or frame-work 8, on which the parts are mounted, and the lowerpart of which may constitute a drawer or casing 9 for the reception ofcertain parts. This supporting structure is connected with theframe-work of the press by means of a hinged joint 10.

The braking generator is indicated asa whole by the numeral 11. Thearmature'12 of this generator is connected with thec rotary support forthe paper roll by` means other than the web, so as to be driven atlconstant speed ratio to the roll. The `armature is connected with theaxial roll support through the instrumentality of a clutch. We prefer togear the armature to the rollspindle and interpose a magnetic clutchbetween the spindle and the gearing. In the particular and desirableconstruction illustrated the spindle is provided at its end adjacent thebraking mechanism with a hollow, conical clutch member or armature 13.An electro-magnetic clutch member 14 is rotatably mounted on the support8, and together with the member 1-3 constitutes means for coupling thespindle 3 with the shaft 15. Details of construction, which are regardedas novel and desirable, will be understood by reference to Fig. 8.

The shaft 15. preferably a tubular membei', is mounted in the bearing 16on the support 8. It is received within a sleeve or telescopic shaftsection 17, the parts l5 and 17 having suitable engagement with eachother so that they are caused to rotate to` ber 14 is connected with thesleeve 17 by means of ay shaft section 19 and two universal joints 20and 21. In this way the compound shaft 15, 17 may be driven withoutwabbling from the spindle 3, even though the shaft and spindle may notbe in longitudinal alinement.

Between the flange 17 on the end of the sleeve 17 and the backof theclutch member 14 we may interpose a casing for inclosing the universaljoints 2O and 21 and conforming to the angular movements of the jointedshafting. This casing may be filled with grease. In the particularconstruction shown, two partially spherical sections 22 are secured tothe flange 17a and the magnetic clutch member respectively. At theirinner ends these sections have universal movement in spherical flanges22a on the ends of a telescopic collar 22", constituting the middlesection of the casing. A spring 24 is interposed between the sections ofthe collar 22h, so as to force them apart, and to tend to hold theclutch member 14 in alinement with its shaft.

-The magnetic clutch member 14 is in the nature of a cup with inner andouter iron walls 25, 26, connected with their bottoms by the iron back27; the coils 28 being wound in the annular slot between the walls. Theface of the memberis beveled off to form a truncated cone to fit theinterior of the soft iron clutch member 13.

The shaft 15 is connected with the armature shaft 29 preferably by meansof a multiplying gearing, shown as consisting of a large gear 30 on theend of the shaft 15 and a pinion 31 on the end of the armature shaft.

Means are provided for locking the suplport 8 to the frame of the press,a suitable embodiment of which is the locking lever 32, having the piece33 which takes over the keeper 34 secured to the side of the pressframe. The lever 32 also constitutes a handle by means of which thebrake apparatus may be swung as ajunit away from the press. Means areprovided whereby movement of theA lever 32`to unlockv the support 8 fromthe press frame also denergizes the electro-magnetic clutch member 14.It is obvious that this may be accomplished in a variety of ways. In Fig, 10 we haveshown a switch 35 which is connected with the lever 32 soas to be thrown open by. the movement of the lever to unlock, and Ato beclosed by the movement of -the lever in locking again. The clutch coilsare shown as connected with wires 250 and 251, which may vlead from Iterminals a and j on the terminal block (see Figs. 9 and 9) to supplythe coils with current. The lever 32 and the switch may be thrown openquickly by a spring 32a, and a latch 32b may hold the locking leverclosed.

The field frame 36 of the generator is mounted rotatably. A convenientconstruction is shownv in Fig. 2, wherein the journal extensions 36a ofthe field-frame turn in external bearings, and the journal portions ofthe armature shaft turn inside the journal extensions of thefield-frame. Ball bearings 38 and 39 may be employed to reduce friction.

The field magnets of the generator are energized preferably by compoundwindings; there being windings 47 in series with the armature, .andwindings 4Fa supplied from an outside source, as shown in Fig. 9. Thecoils 47a are supplied with current from an outside circuit throughterminals a and j on the terminal block 50, and wires 47b and 47 c.

This form of winding enables the generator to produce an adequatebraking current at the slow yspeed subsequent to starting.

' In accordance with the invention means are provided whereby rotationof the fieldframe 36 under the torque of the armature of the generatorreduces the braking effect as the speed of the armature of thelgenerator increases. In `the particular embodiment of the inventionillustrated the rheostat 40 is controlled by the field-frame, toy placemore or less resistance in series with the armature brushes 41 and 42,which are mounted on the field-frame so as to rotate therewith. Variousmeans may be employed to this end. We prefer to mount a large gearsegment 43 on the field-frame, meshing with which is a pinion 44, to theshaft 44a of which is secured a support 44b carrying a brush 46, whichis thereby rotated about a stationary commutator 45. This brush isconnected with the armature brush 41. The circuit may be traced in Fig.9 from the brush 41, through the series coilsy 47 of the field polesalong wire 48 to the terminal on a suitable terminal block 50, thence bywire 51 to the rheostat'brush 46, thence through the icommutator segmentand as many resistance coils'as are included in cir- 1cuit, to the' wire52 leading from the rheostat to the terminal .c on the block, and fromthence by wire 54 to the other armature `brush 42. The parts are soarranged and related that the field-frame turns under the torque of thearmature of the generator which operates the rheostat to cutprogressively more resistance into the armature circuit, thusdiminishing the strength of the braking current generated by thearmature rotatingI at increasing speed. Normally, that is, at starting,as indicated in Fig. 14, the brush 46 is positioned so that few or noneof the resistance elements are in circuit. The resistance elements firstcut in are of low resistance, and the resistance of the several elementspreferably increases in the order in which they are cut into the circuitas the commutator revolves. `Thus, as the brush4 46 is rotated by thefield-frame, more resistance elements are constantly included 'of therheostat. Here the starting commutator segment is shown long, so thatboth the brush 46 and the brush .61 (presently to be described) may restthereon. This view indicates that the resistance' elements increasein'value.

In 'accordance with the invention means are providedfor offeringdiminishing opposition to the turning of the field-frame under thctorque of thearmature as the unwinding of the paper roll proceeds, andfor automatically turning the field-frame backward and thereby cuttingout resistance when the web roll stops or slows down. Preferably,mechanical means are employed for this purpose. In the particularconstruction illustrated a weight (0 is utilized., and its leverage toturn the field-frame backward is progressively diminished by means of acam 71. As shown more particularly in Figs. 5 to 7, the cam 71 ismounted von a shaft'72, on which is-a beveled pinion 73 meshing with abeveled gear 74 on the fieldframe; so that the cam is rotated atincreased sieed by the rotation of the fieldframe. 'l he weight 70 isconnected with the cam by means of a cord or other flexible connector75, which is wrapped upon the surface of the cam as the cam turns.Preferably, the weight is mounted slidably on an arm 76, which ispivoted at one end as at 77 and has a pulley 78 at its other end overwhich the cord is passed. The other end of the flexible connector 75 issecured to a suitable stationary support, as indicated at vindicated atbeing provided for securing theV weight at any point of adjustmentthereon.

Means are provided whereby the generator may be caused to act as adynamic brake to secure a prompt stoppingof the paper roll. This meansis preferably controlled by the emergency means, or red push button, forstopping the press. This means operates to cut out a material amount ofthe resistance 40 which happens to be in circuit with the armature ofthe generator, so that the generator produces a suddenly increasedcurrent. At the same time the field-frame is locked against furtherrotation. In the particular construction illustrated a solenoid isprovided with a contact 56 on its core arranged to bridge two contacts57 and 58. Contact 57 is connected Vby .wires 59 and 60 and the terminald on the terminal block with an eXtra brush 61 bearing on the Commutator45 and carried by the same support 44b as the brush 46, both brushesbeing insulated from their support. The contact 58 is connected with theWire 51 leading from the contact I on the-terminal block. When thesolenoid is energized to bridge the contacts 57 and 58, the armaturecurrent passes from the wire 48 and the wire 51 to the contact 58,thence to contact 57, along the wire 59 to terminal d on the terminalVblock, thence by wire 60 tobrush 61, through the resistance elements inrear of this brush to wire 52, and thence back to the armature, as

before. In this way, the resistance coils or i sections included betweenthe brushes are in effect cut out. Thus, a Vmaterially larger current isgenerated by thc armature, and a correspondingly greater brakingresistance is offered to the turning of the paper roll. Simultaneouslywith this cutting out'of resistance from the armature circuit, thefield- Vframe is locked against rotation, thereby locking the brushes 46and 61 in-relation to the commutator 45. To this end we have shown acatch 62, which is swung by the core of the solenoid 55 into engagementvwith the teeth of the gear segment 43 on the field-frame. The particularconstruction of the solenoid with its movable contact and the catch isshown in Fig. 4. As there illustrated av spring 63 may be interposedbetween the catch 62 and the core of the vsole-v tact 56 will still bedrawn up against the contacts 57 and 58.

The solenoid 55 is connected with an outside circuit through wires 64and 65.` Fig. 12 shows an arrangement of Wiring whereby the solenoid isenergized'when the means for effecting an 4emergency stop of the pressor other instrumentality unwinding the material is operated.v Forpurposes of illustration the electrical system whereby the press iscontrolled manually is somewhat simplified, because the system is knownand is not our invention. 15() indicates the press- 'driving motor,thefield of which 'is connected directly across the mains. When thepress is running, the armature current flows from the plus main' alongwire 151, through as much of variable resistance 152 as is in ycircuit,' by movable contact153 to contact 154, thence by wire 155 tocontact'156, i

then ce by bridging contact 157 to Contact 158, thence to armature brush159, and from the other armature brush 160 by wire 161 to the minusmain. To stop the press suddenly the push-button 162 is closed. Thiscauses current to pass through the solenoid 163, and thence by wire 164to the minus main. The consequent lifting of the core of this solenoidbreaks a circuit between contacts 165 and 166. This circuit may betraced from wire 167 to wire 168, thence through solenoid 169 to wire164|. The consequent denergizing of solenoid 169l causes the causing themotor to act as a generator vide a plunger 17 4, which is depressed bythe driven by the press, whereby the press is stopped suddenly by adynamic braking action. "All of the foregoing is old. We procore of thesolenoid 169, and which closes the circuit through the solenoid 55 forapplying the dynamic brake tothe Web roll. We have shown the plunger176i as provided with a rack 175 which meshes withy a pinion carrying acontact arm 17 6, which is' adapt. ed to bridge contacts 177 and 178.Vhen this happens current flows along wires 167, 179 to contact 177, to'contact 178, by wire 180 to solenoid 55, and thence by wire 181 to theminus main. A spring 182 may re turn the rod 174, and a dash. pot 183 orother timing device maybe employed to slow up the movement, so that thecircuit is completed across contacts 17 7 and 178 for a sufficientperiod of time to maintain the dynamic brake on the paper roll as longas is necessary. A

Inr accordance lwith the invention means are provided for assisting thebraking effect of the generator in stopping the roll when the press isstopped, in event either of an ordinary stopping of the press or anemergency stop. Preferably, this electro-magnetic brake is energized bycurrent taken from the armature of the braking generator. This magneticbrake may be applied to any suitable part connected with the paper roll;

but best results are secured by causing it to Y act upon a part which isrotated at comparatively high speed, since in this wav a Y small amountofl magnetism will effect a quick stopping.. In the particularconstruction'illustrated a fixed magnet 81 is wound with coils 82adapted to be placed in circuit with the armature. This magnetv is sup--ported by any suitable means, such as indicated at 83, on a stationarysupporting part of the frame-work x8. It coperates with an armature 84:`secured to the face of the pinion 31. toward and from the magnet, towhich end it may be secured tothe pinion by means of screws 85, whichpermit limited movement of thearmature. A spring-actuated device 86,preferably mounted on the magnet, is 'provided for separating thearmature from the magnet when the current through the coils is broken;so thatk residual magby current from the armature of the gen- Thisarmature 84; is movable an arrangement.

Since the magnet 81 is energizeddynamic brake effect is secured toproduce an emergency stop, than at ordinary stopping. In other words,the reduction in the resistance in circuit with the armature and thelocking of the field-frame not only f,

causes the generator to actv as a dynamic` brake, but the increase ofcurrent .also causes the magnetic brake 81 to exert an abnor- 'f words,the magnetic brake is controlled in an indirect manual manner. Thearmature current of the generator normally enters at Contact 88, passesthrough the spring contact member 91, thence to contact 92 on thearmature member 89,.and out at the contact to the rheostat. When thearmature member 89 is drawn over by the magnet 87, it separates thecontacts 91 and 92 and closes the lcontacts 92, and 98. The armaturecircuit now passes from terminal 88 along the' wire 94 to the coils ofthe brake magnet 81, thence b v wire to contact 93, thence by contact 92and the armature member 89 to the rheostat. The contact members 91 and-93 are both preferably spring yielding memtact` 93 is mounted on aslidable rod which v is urged forward by a spring coiled about it. IVhenthe contact 92 is moved to the left the contact 93 follows it by virtueof its coiled spring and remains in touch with contact 92 until thelatter comes against contact 91. Further movement of contact 92 to theleft moves it away from contact 93, which is held against furtherfollowing movement by an enlargement or stop on the rear end of its rod.

The wiring whereby the controlling magnet 87 is energized by thepush-buttons which effect the stopping of the press may be widelyvaried. In Fig. 12 we have shown The controlling magnet 87 has two coils96 and 97. 96 is connected in parallel with the solenoid 55 across thewires 180 and 181, so that this coil is energized simultaneously with anemergency stop of the press, to cause current to flow through thebrakingmagnet 81. The magnet is also energized to the same end when thepress is slowed down or brought to a gradual stop, for which purpose apushbutton 195 is operated. Current then flows from the plus main bywire 98, switch 195, wire 99,- to the other coil 97, and thence by wire181 tothe minus main. The system for slowing down or gradually stoppingthe press is not our invention and is well known. We have thereforeillustrated it in a somewhat simplified manner. When the pushbutton 195is operated, current fiows along 'wire 98, wire 100, through solenoid101, to

push-button 102, thereby energizing a magnet '103, which releases a dog104 that .en-

gages automatically with teeth on the stem of the contact 153.

` In accordance with the invention means are provided for securing orlocking the field-frame against return to normal position, when apredetermined point in its turning under "the torque of the armature hasbeen reached.'V This point corresponds to a speed due to a very smallroll, which would offer so much resistance to the 'pull of the paperweb'that the latter might be torn were the braking current to reachmaximum strength after again starting the press. The means for latchingor preventing thereturn of the lfield-frame may be Widely varied. In theparticular construction illustrated a plate 105 is secured to one end ofthe fieldframe, and a pin 106 .projects from this plate in position toride over a pivoted latch 107, which falls behind the pin, so that whiletheeld-frame may continue its rotation. it cannot return past the pointdetermined by the latch. Means are provided .whereby thev release ofthis latch is necessitated by the act of replacing an exhausted roll bya new one. widely varied. We havev shown a rod 108 mounted slidably inguides 109 on the support 8, for releasing or removing the latch fromdetaining position with respect to the' pin 106. Preferably the latch ispivotally mounted on a head at theupper end of this rod. A spring 110servesto holdy the latch yieldingly in the path of the pin. Raising ofthe rod 108 lifts the latch 107 out of the path of the pin 106, so thatthe field-frame is free to return to normal position. The rod 108 may beraised by any suitable means dependent upon the replacement of the paperroll; and for this purpose we may make use of a spring 110i. We haveshown the removal of the latch from detaining position as beingcontrolled by the hand-lever 32, which locks the brake mechanism as awhole to the side of the press. It is neces- Such means may bev sary tomove this lever to unlock the mechanism from the press, so that thesupport 8 may be swung outward, in order to permit the removal of theold spindle andthe insertion of a lnew roll. The spring 110 is placedunder compression by the lever 32 when the latter is in its latchedposition.

To this end We may pivot the lower end of the rod 108 to an arm 111,-which is pivoted at 112 to 'the support 8. A link 113 is pivoted at itsupper end to the lever y32, and its lower end has a slot 114 receivinganpi'n 115 projecting from the arm. When the lever 32 is raised, eithermanually or'byv the spring 32, the link 113, which formerly held the arm111 Vdown against the action of the spring 110, permits the arm and therod 108 to rise under the action of this spring.

Means are also provided whereby the field-frame must be positivelyreturned to normal position in order to replace the paper roll. This isdesirable, inasmuch as the weight acting upon the portion of the cam 71of the smallest diameter might not be able to eiiect the return of theieldframe at this time. The means may be Widely varied. In theparticular construetion illustrated we have shown a second pin orprojection 116 on the plate 105, this pin being in position to 'clearthev latch 107, but to be contacted and pushed by the head on .the endof the rod 108, when this rod rises.-

Thus, a positive impulse is imparted to the field-frame to return it tonormal position.

Means are provided whereby the press is automatically stoppedwhen theroll has diminished in size to a predetermined degree; so that the webcannot b'ecome entirely'exhausted. Such means may be widely varied. andeither electrical or mechanical instrumentalities may be employed. Inthe-particular form of means illustrated we employ a centrifugalg0vernor200 driven-by the roll. This governor isshown mounted on thegear 30. Its pivoted arms 201 ily out at a predetermined speedv againstthe tension vof the spring 202 and grip arctatable incasing member 203,,turning the latter. A sliding contact member 201is connected to thismember 203, and has an vfor ,regulating the margins of the web, so as tokeep the web running true with equal margins at both sides (describedand claimed in our cop'ending application Serial Number 3591, filedJanuary 2l, 1915, for margin regulating mechanism for web rolls). Forthis purpose we employ the slidable shaft section 17. This shaft sectionmay be moved longitudinally, so as to shift the roll spindle through theconnection of the clutch 14, either by mechanical or by electricalmeans. le prefer to combine both. In the particular constructionillustrated a shifting lever 123 engages with a collar 124 on the shaftsection. At its rear. end the lever is pivoted by means of a slot on asuitable pin 125, and at its front end it is pivoted to a nut 126 imounted on a screw 127. This screw is journaled at its ends in suitablebearings 128, and carries a bevel gear 129. VVlth this gear mesh twoother bevel gears 130 and 131.

Gear 130 is mounted on a hand-wheel 132 whereby the margin-shifting maybe effected manually by mechanical means. For operating themargin-regulating mechanism electrically we employ a suitable motor 133,and meansfor causing the, armature of the motor to run in eitherdirection. A worm 134 is mounted on the end of the shaft of the armatureof this motor, and meshes with a worm-wheel 135, which is mounted on thesame shaft as the bevel gear 131. Preferably this worm-wheel is mountedloosely on its shaft 136 and is yieldingly coupled therewith by a spring137, which forces the wheel down upon a` friction surface member 138secured to the shaft. This frictional slip connection between themargin-regulating motor 133 and the shaft member 17 is a desirabledetail, because it permits relative slipping between the shaft 136 andthe armature of the motor, even when the spindle has been shifted by themotor as far as is possible, or when the spindle p is shifted by thehand-'wheel 132.

Figs. 9 and 9a indicate a form of wiring for causing the armature ofthemarginregulating motor to turn in either direction. Vires 138 and 139connect the field coils with the terminals g and j on lthe terminalblock, conductors 140 and 141 connect the armature brushes with theterminals and i. lVhen the switches L and R are in the positions shown,no current passes through the motor, which isidle. 7hen the switchL ismoved against the contact 142, the current passes from the plus linewire. and wire 143, to wire`138, through the field coils, to wire 139,to wires 144 and 145, to contact 142, thence through the blade of theswitch to terminal z', thence by wire 140 to the armature, thence bywire 141 to terminal h, and thence by wire 146, switch R and wire 147 tothe minus line wire. lVith the switch L in the position shown and theswitch Rin port 8 is locked against the side of the pressframe, that thepress and the paper roll spindle yare at rest, and that the paper rollis exhausted. In order to place a new roll in. the press, the latch 32hwhich holds the lever 32 in its locking position with relation to thepress-frame is released, and the spring 32a which actuates the lever. 32throws the lever quickly to unlocking position; This act throws open theswitch 35, thus breaking the circuit through the coils of the magneticclutch 14. As a matter of fact,l this switch preferably breaks all ofthe circuits which are supplied from the line wires indicated in Fig. 9.The movement of the lever to unlocking position also removes the latch107Y from retaining position with reference to the field-frame, so thatthe latter may be turned back to normal position 1n the mannerdescribed. The support -8 is now swung away from the press frame,

-to lock the mechanism asa whole in operative position. When the leveris forced down and held` in locking position by the latch 32h the switch35 is closed. so that the magnetic clutch 14 is energized. The web isthreaded into the press and the latter is started. The rollbegins tounwind, slowly at rst and with increasing speed until the press isrunning at its normal speed. lVhile the press is getting up to normalspeed the generator driven from the paper roll is producing current. Thefield-frame may commence to turn under the torque of the armature evenbefore the press has reached nor- Vmal speed, so as to cut resistanceinto the armature circuit. However, the first resistance elements are ofso low a value that the as the roll diminishes in size. The coaction ofthe cam and the variable resistance 1s y such that the torque of thearmature cannotthrow the field-frame over at once. ,The opposing effortsof the armature and of. the

weight bear always such relations that they field-frame is turnedgradually.

Since the variation in the braking resistance of the generator is underthe control of the angular velocity of the paper roll it follows thatthe braking effect is again increased when the paper roll is sloweddown,

due to the slowing or stopping of the press. Moreover, at the stoppingof the press the magnetic brake 81 is brought into action,

' to insure that the paper roll will not overrun. In event of anemergency stop of the press the armature circuit of the generator isrelieved of a considerable amount of the resistance that happens to bein circuit, and the field-frame is locked, so that a considerablyincreased current is generated, with a consequent dynamic brakingeffect. This increased current, also, energizes the braking .magnet 81with increasing strength, so that a very quick stopping of the roll iseffected. When the armature of the generator has reached a predeterminedspeed, corresponding to a predetermined diminished size of the paperroll, the latch 107 comes into operation to prevent the field-v framefrom turning back to normal position in event of stopping of the press.`When,

however, a new roll is to be inserted, this operation necessitates therelease of the field-frame from the detention of the latch 107, andcompels the return of the ieldframe to normal position. In event thatthe diminishing size of the roll is disregarded by the attendant and thepress is not stopped in time to prevent the exhaustion of the web, themeans under the control of the speed of the roll. acts automatically tostop the press. From time to time the margin of the webmay be regulated,either by means of the hand-wheel 132, or by the motor 133.

While for purposes of illustration we have shown one embodiment andapplication of our invention, it will be understood that numerous otherembodiments and applications are within the'scope of the invention.Numerous changes in structure, function and operation, includingAreversals, are permissible. An apparatus embodying our invention formaintaining an approximately uniform tension on a yweb or other materialbeing wound or unwound, including a r0- tary` electric machine connectedto the rotary support of the roll or the like and a floating memberrotatable under the torque of the rotor of the machine to control a,variable impedance, may be embodied in a great variety of ways and putto a great variety of uses.

The margin-regulating means vshown and described herein is not claimedin this case, but in a divisionalapplication, Serial No.

l3,591, filed vJanuary 21, 1915.

We claim: Y i

1. In a tension-controlling mechanism,- the comblnation of a rotatablesupport forv a roll of material, a braking electric generator, drivingconnections other than the material between said support and thegenerator, and automatic means for varying the braking effect of saidgenerator; v 2. In a web tension mechanism, the combination of an axialsupport for the roll, a braking electric generator, drivingconnectionsbetween said support and the generator whereby the armatureof the latter` is driven at a constant speed ratio by the former, andautomatic means for varying the braking effect of said generator.

3. In a web tension mechanism, the comvelocity of the roll for varyingthe braking effect of said generator.

e5 bination of a braking electric generator,l means for connecting thesame with the web f 1 roll, and means controlled by the angular 4. In atension-controlling mechanism, y

braking electric generator, means for coni necting the same with saidsupport so as to be driven at constant ratio thereby, and

means controlled by the increasing angular velocity'of the roll fordiminishing the braking ei'ect of the generator in accordance with thediminishing size ofA the roll.

6. In a web tension mechanism, the combination of an axial web rollsupport, a braking electric generator, a clutch for connectingthe samewith said support, and' automatic means for diminishing the. brakingefect of the generator as the web roll is unwound.

7 In a tension-controlling mechanism, the vcombination of a rotarysupport for a roll of material, a braking electric generator,

a clutch lfor connecting the same with said support, and automatic meanswhereby thel braking elfect first increases to a maximum and thendiminishes in accordance with the.

diminishing size of the roll.

8. In a web tension mechanism, the ccmbination of a braking electricgenerator,l

means for connecting the same with the web roll, and means controlled bythe angular velocity of the roll whereby the braking eiect of thegenerator first increases to a maximum and then'diminishes as the Webyfis unwound from the roll.

Q 'jIn a tension-controlling mechanism, the `combination or a rotatablesupport for a roll of material, electro-magnetic braking meansconstantly acting on said supportv during-the movement 'of the material,and means controlled by the angular velocity of the roll for varying thebraking effect' of said means.

10. In a web tension mechanism, thecombination of" means for supportingthe Web roll, electro-magnetic braking means `constantly acting on saidrollv during the unwinding thereof", and means controlled by the angularvelocity of the roll for varying the braking effect of saidfmeans.

1l. In a tension-controlling mechanism, the combination of a brakingelectric generator, means f'or supporting a roll of material, means forconnecting the generator with the roll, automatic means for varying thebraking effect of the generator as .the roll changes in size, anelectro-magnetic brake for stoppingthe roll, means for-actuating thesaid brake, and means for varying the strength of the braking actionthereof in accordance with the size of the roll.

12. In a Web tension mechanism, thev combination of a braking electricgenerator, means for connecting the same with the `webvroll, a variableimpedance, and means controlled by the angular velocity of the roll forvarying said impedance so as to vary the braking effectof saidgenerator.

13. In a tension-controlling mechanism, the combination of a rotatableaxial support for a roll of material, a braking electric generator andmeans whereby the same is driven at constant speed ratio by saidsupport, a varlable electric resistance, and means controlled by thechanging angular velocity of the roll for varying the braking effect ofsaid generator.

14. In a Web tension mechanism, the combination of a spindle forsupporting the roll, a` braking electric generator driven by saidspindle, and automatic means for varyingY the braking effect of saidgenerator.

15. In a tension-controlling mechanism, the combination of arotatableaxial support for a roll of material, a. braking electric generatordriven by said support, and means controlled by the changing velocity ofthe support for varying the braking effect of said generator. l

16. In a tension-controlling mechanism, thecombination of' a rotatablesupport for a` roll of. material, a braking electric generator includingrotatable magnetic means moved by the torque of the rotor of saidgenerator,

and means operated by said rotatable mag-- netic means for varying thebraking effect of said'generator. -v

17. In a web tenslon mechanism, the combination` of a braking electricgenerator, means for connecting the same with the Web roll, and meansincluding a rotatable magnetic member moved by the torque of the rotorof said generator for varying the braking effect of said generator asthe roll un- Winds. f' i 18. In a web tension mechanism, the combinationof a braking electric generator, means for driving the same at constantspeeol ratio from the web roll, said generator including a memberrotatable under the torque of its rotor, and means controlled by saidmember for varying the braking effect o1 said generator. Y

19. In a tension-controlling mechanism, the combination with an axialsupport for a roll of material, of a braking electric generator, aclutch for connectingY said generator With said support, said generatorincluding a member rotatable under the torque of its rotor, and meansoperated by said member to vary the braking effect of the generator. i

20. In a Web tension mechanism, a braking electric generator, means forconnecting the same With the web roll, said generator having a rotatablemember moved by the torque ofV its rotor, means forl offeringdiminishing opposition to the turning of said member, and means operatedby said member for varying the braking effect of the generator. v

21. In aweb tension mechanism, a brak ing electric generator, meansforconnecting the same with the Web roll, said generator having a rotatablemember moved by the Atorque of its rotor, mechanical means for exertinga diminishing effort to turn said member in the contrary direction,and'means operated by -said member for varying the braking effect of thegenerator.

22. In a Web tension mechanism, a braking electric generator, means forconnecting the same with the Web roll, said generator having a rotatablemember moved by the riablc electric resistance controlledby-said memberso as to vary the braking effect of the generator, and means forconnecting said generator. with the roll support.

24.- In'a Web tension mechanism, the comf bination of 'a brakingelectric generator having a. floating field-frame means whereby' fooytorque 'of its rotor, means for exerting a said generator is driven bythe web, means for exerting a diminishing opposition tothe rotation pfsaid field-frame under the torque of the generator armature, and meanscontrolled y said rotatable field-frame for varying the braking effectof the generator.

l 25. In a tension-controlling mechanism,

' the combination of a rotatable support for a roll of material, abraking electric generator having ay ioating field-frame, a clutch for-connecting said vgenerator with said support, means" for exerting achanging contrary turning eiort on said field-frame,- and meanscontrolled by said rotatable eldframe for varying the braking effect ofthe generator.

26. In a web tension mechanism, thev combination of braking electricgenerator having a oating Afield-frame means whereby said generator isdriven by the web, meansr the movement of said member, a variableelectricalresistance connected with the generator for varying thebraking eect thereof, and means whereby said resistance is varied bysaid rotatable member.

28. In a web tension mechanism, the com-y bination of a braking electricgenerator having a member rotatable under the torque of its armature,means whereby the generator is driven by the web, mechanical means forexerting a torque on said member contrary to the torque of the armature,means whereby the torque of said mechanical means is progressivelydiminished, a variable electrical resistance connected with thegenerator, and means whereby 'said resistance is controlled by saidmember so as to diminish the braking current as the speed of thegenerator armature increases.

29. In a tension-controlling mechanism, the combination of means forsupporting a roll of material, a braking electric generator having amember rotatable under the torque of its armature, means whereby thegenerator is driven by the roll,.a weight opposing such movement of saidmember, a cam for automatically varying the leverage of said weight, avariable impedance connected with the generator, and means whereby saidimpedance is controlled by said member to vary the braking eiiect of thegenerator.

30. In a web tension mechanism, the combination of a braking electricgenerator having a member rotatable under the torque of its armature,means whereby the generator 1s drlven by the'web, mechanlcal means forexerting a torque on said member contrary to the'torque of the armature,a cam driven by said member for varying the moment of said means,v avariable impedance connected with the generator, and means whereb saidimpedance is controlled by said mem er to vary the braking ciiect of thegenerator.

31. In a web tension mechanism, the combination of a braking electricgenerator having a member rotatable under the torque of its armature,means whereby the generator is driven'by the web, returning means for`exerting a contrary torque on said member decreasing as the member isrotated by the torque of the armature, means oradjusting the torque ofsaid` returning means at will, and a variable electrical resistanceconnected with the generator andv controlled by said member to diminishthe 'braking effect of the generator as the speed of the armatureincreases.

32. 'In a tension-controlling mechanism,

the combination of means for supporting a v i roll of material, abraking electric enerator having a member rotatable under t e torque ofits armature, means whereby the generator is driven by the material, anadjustable weight controlling the movement of said vmember, and avariablel electrical resistance connected with the generator andcontrolled by said member to vary the braking eiect of the generator.

33. In a web'tension mechanism, the cornbination of a braking electricgenerator having a member rotatable under the torque of its armature,means whereby the generator is driven by the web, a-cam connected withsaid member, a weight and a flexible con' nector suspending the samefrom the cam, and a variable impedance controlled by said member forvarying the braking current produced by the generator. j 34. In atension mechanism, the combination of a' rotatable support for a roll ofmaterial, a braking electric generator driven by said support and havinga member rotatable under the torque of its' armature, a weight slidablymounted on a pivoted arm, a cam connected with said member, a liexibleLOE connector connecting the cam and the arm,

and a variable electrical resistance controlled by said member forvarying the braking current produced by the generator.

35. In a web tension apparatus, the combination of a rotatable supportfor the web roll, a braking electric generator driven therebyA andhaving a member rotatable under the torque of its rotor, mechanicalmeans for opposingsuch rotation of said member, said means being adaptedto have decreasing eect as the said member is so turned, and a variableimpedance controlled bysaid member while turning to vary the 4brakincurrent. f

36. a'web tension apparatus, the combination of ay rotatable memberdriven by the 'web, a braking electric generator, clutch c011- means forvarying said resistance as the web roll unwinds.

37. In a web tension apparatus, the combination of a braking electricgenerator, means for connecting the same with the web roll, a variableresistance in circuit with the .armature of said generator, and meanscontrolled bythe angular velocity of the web roll for varying ,saidresistance.

38. In a tension apparatus, the combination of means for supporting aroll of ma terial, a brakingelectric generator, means whereby the sameis driven from said supporting means, said generator having a memberrotatableY under Ythe torque of its armature, and a variable electricalresistance in series with the armature controlled by said member.

39. In a tension apparatus, the combina tion of means for supporting aroll of material, a braking electric generator, means whereby the sameis driven from said supporting means, said generator having a memberrotatable under the torque of its armature, means for exerting adiminishing contrary torque on said member as it turns under the torqueof the armature, a variable electrical resistance in circuit with thearmature, and means whereby said member in rotating under the torque ofthe armature cuts in increasing resistance.

40. In tension apparatus, means for supporting a roll of material, abraking electric generator, means whereby the same is driven from thematerial, a variable resistance for varying the braking ettectrof thegenerator, automatic means for controlling said resistance in accordancewith the changing size ofthe roll, and means forcutting out aconsiderable amount of the resistance so as to effect a quick stoppingof the roll.

42. In a printlng press, a braking electric generator, means forconnecting the same with the web-roll, a variable electrical resistancefor varying the braking effect of the generator, automatic means forvarying said resistance asy the roll diminishes in size,

emergency` means for stopping ther press, p

pedance aiiecting the generator so as to produce a dynamic brakingeffect.

44. In a tension apparatus, means for sup- -porting a roll of material,a braking electric generator, means whereby the same is driven from thematerial, a variable resistance for varying the braking effect of thegenerator,

said generator having a iioating ield, means I whereby said fieldcontrols said resistance and means for simultaneously locking Saidfield-frame and materially altering the amount of resistance affectingthe generator.

45. In a tension apparatus, means for supporting a roll of material, abraking electric generator, means whereby the same is driven from thematerial, a circuit with a variable resistance for varying the currentproduced by the generator, two contact members cooperating with thevariable resistance, one being normally in closed circuit and the othervnormally in open circuit, and emergency means for changing the circuitto include the second contact member so as to materially change theamount of resistance affecting the generator. y

46. In a web tension apparatus, a braking electric generator, meansforconnecting the same with the web roll, said generator having afloating field,. a circuit with a variable resistance for varying thebraking eect of the generator, two contact members coperating with thecontacts of the resistance'sections, means whereby said ield-frame prO-duces relative movement between the con.- tacts ofthe resistancesections and the 'contact members, and emergency means forsimultaneously locking said field-frame with the contacts and contactmembers and for changing the circuit to include thesecond contact memberso as to materially change the amount of resistance aecting thegenerator.

47. In an apparatus for controlling web rolls, a braking electricgenerator, means for connecting the same with the web roll, auto- `maticmeans for varying the lbraking eii'ect of said generator as the rollunwinds, vand 'i an electro-magneticbrakeY for assisting in stopping theroll.

48. In a tension apparatus, means for sup- 131( porting a roll ofmaterial, a braking electric generator, means for connectin the same vwith the roll, automatic means or varying the strength of currentproduced by said generator as the roll revolves, an electromagneticbrake for assisting in stopping the roll, and means whereby said brakeis energized by current from said generator. l

, 49. In a printing press, a braking electric logenerator, means forconnecting Athe'same Awith the paper roll', automatic means for varyingthe braking eiiectof said generator as the roll unwinds, anelectro-magnetic brake for assisting in stopping the roll,

means for stopping the press, and means controlledl thereby forcompleting the circuit through the coils of sald electro-magnetic brake.

50. In a printing press, a braking electric generator, means forconnecting the same with the paper roll, automatic meansvv for v varyingthe strength of current produced by said generator as the roll unwinds,an electro-magnetic brake for assisting in stop# ping the roll, meansfor stopping the press, and means controlled thereby for causing saidbrake to be energized by current from .said generator.

51. In an apparatus for controlling rolls of material, abrakingelectricV generator, means for connecting the same with the roll,automaticmeans for varying the braking effect of said generator as theroll revolves, a Xed electro-magnetic brake, a rotatable. armaturevtherefor connected with the roll, and means for energizing said brake toassist in stopping the roll.

52. In an apparatus for controlling rolls of material, a brakingelectric generator, meanslfor connecting the same with the roll,automatic means for varying the braking effect of said generator as theroll revolves, a fixed electro-magnetic brake, a plate armature mountedloosely on a rotatable support connected `with the roll so as to bemovable toward and from the electro-magnetic brake, and spring means forseparating the magnet ,and armature.

5 8. In an apparatus for controlling rolls of material, a brakingelectric generator, means for connecting the same with the roll, acircuit including a veriable resistance for varying the current producedby the generator, automatic means for controlling said variableresistance to decrease the braking current as the roll revolves,stopping means for materially altering the amount of resistanceaii'ec'ting the generator so as to increase the braking current, anormally. denergized electro-magnetic brake, and means whereby it issupplied with current from said generator upon the operation of saidstopping means.

54. In aweb tension apparatus, a braking electric generator, meanswhereby the same -the generator, means for exerting a diminis driven bythe web, said generator including a floating member rotated by thetorque of its armature, means whereby said member in so turningdecreasesthe braking elect of ishing contrary turning eiiect on said member whenthe latter is rotated by the armature, and means for preventing saidmember from returning to normal position after turning to apredetermined degree.

55. In a tension apparatus, a braking electric generator, means wherebythe same is driven from the material under tension, said generatorincluding a floating member rotatedy by the torque of its armature,means whereby said member in so turning decreases the braking effect ofthe generator, means for exerting a diminishing contrary turning effecton said member when the latter is rotated by the armature, and'anautomatic latch coperating with said member at a predetermined degree ofrotation.

56. In a tension apparatus, means for receiving a rotary axial supportfor a roll of material, a braking electric generator, means whereby thesame is driven by said rotary support, means for automatically varyingthe braking eect of said generator including a floating member rotatableunder the torque of the armature of the generator, means for preventingsaid member Jfrom returning to normal positionafter turning to apredetermined degree, and means whereby replacement of .the rotarysupport necessitates the return of said member to normal 100 position57. In a web tension apparatus, means for receiving the web roll, abraking electric generator, means whereby the same is driven by the web,means for automatically varying 'the braking ei'ect of said generatorincluding a floating member rotatable under the torque of the armatureyof the generator and means tending to return the member lto normalposition, an automatic latch coperating 11'0 with said member at apredetermined degree of rotation, and means whereby replacement of theroll necessitates the release of said member from the detention of saidlatch.

58. In a web tension apparatus, means for receiving the web roll, abraking electric generator and means whereby the same is driven by theweb, means for automatically varying the braking eiiect of saidgenerator 1420 including a oating member. rotatable under vthe torque ofthe armature of the generator,

and means whereby replacement of the roll compels the return of saidmember to normal position.

59. In a web tension apparatus, means for receiving the web roll, abraking electric generator and means whereby the same is driven by theweb, means for automatically varying the braking eect of said generatorl@ including a floating member rotatable under the torque of thearmature of the generator and means forexerting a diminishing contraryturning effect on vthe member during 5 such turning, means for impartinga returning impulse to said member, and means whereby the replacement.of the roll' occasions the actuation of the last-named means.

60. 1n 'a web tension apparatus, a rolll eeiving a rotatable axialsupport for a roll of material, a braking electric generator, aclutchfor connecting the same with said support, means for automaticallyvarying the braking effect of the generator including a floating memberrotatable under the torque of the armature of the generator, and meanswhereby disconnection of said clutch necessitates the return of saidmember to normal position.

62. In a web tension apparatus, a frame for receiving. the web roll, asupporting structure movable toward and from said frame, a brakingelectric generator mounted on said supporting structure, means wherebysaid generator is driven by the roll, means for automatically varyingthe braking effect of said generator including a floating memberrotatable under the torque of the armature of. the generator, meansforpreventing said` member from returning to normal position afterturning to a prede# termined degree, and means whereby moving saidsupporting structure away from` said frame'necessitates the release ofsaid member from the detention of the last- ,named means.

63. In a web tension apparatus, a frame for receiving the web roll, asupporting structuremovablel toward and from said frame, a brakingelectric generator mounted on said supporting structure, means wherebysaid generator is driven by the roll, means for automatically varyingthe braking effect of said generator including a floating memberrotatable under the torque of the armature o'f the generator, means `foreX-l erting a returning effort on said member,

' and means whereby moving said support away from said framenecesistates the actuation of the last-named means. 64. In a tenslonapparatus, means for receiving a rotary support for a'roll of material,a. braking electric generator, means whereby the same is driven by -theroll, means for automatically varying the braking effector saidgenerator including a loat.

ing member rotatable under the torque of the armature of the generatorand means port necessitates the release of said memberV from thedetaining means and the actuation of the returning means.

65. In a' `tension apparatus, a frame for receiving a roll of material,a'movable supporting structure, means for locking thesame in relation tosaid frame, a braking electric generator mounted on said vsupportingstructure, means whereby the generator is drivenby the roll, means forautomatically varying thebraking edect of said generator including afloating member rotatable under the torque of the armature of thegenerator, means from preventing said member from returning to normalposition after turning to a predetermined degree, and means wherebyunlocking of said locking means necessitates the release of said memberfrom the detention of the last-*named means.

66. In a tension apparatus, a frame for receiving a roll of material, amovable supporting structure, means for locking the same in relation tosaid frame', a braking electric generator mounted on said supportingstructure, means whereby the generator is driven by the roll, means forautomatically va'rying the braking efect of said generator including afloating member rotatable under the torque of the armature of thegenerator, and means whereby unlocking of said locking meansnecessitates the return of said member to normal position. Y

67. In a Web tensionl apparatus, the combination with a frame and arotary web roll support mounted thereon, of a movable supportingstructure at one side of the frame,

a braking electric generator mounted on the supporting structure, andmeans including a clutch for connecting said generator with said rotaryvweb roll support.

68. In a tension' apparatus, the combination with a frame and a rotaryroll support mounted thereon, of almovable supporting structure at oneside Vof the frame, means for locking said supporting structure inrelation to the frame, a braking electric generator mounted on thesupporting structure,

' and means including a clutch for connecting said generator with saidrotary roll support.

69. In a tension apparatus, the combination with a frame for receiving aroll of material, of a pivoted supporting structure at

